Portuguese police are said to be investigating a new lead in the Madeleine McCann case, suspecting a man who died in a tractor accident four years ago of being her kidnapper.

The new line of inquiry focuses on a former employee of the Ocean Club, the complex in the Algarve where the child’s family were staying when she disappeared more than six years ago.

The unnamed man, who died aged 40 in a tractor accident in 2009, may have been motivated by revenge after being sacked by the hotel resort, Portugal’s Correio da Manha newspaper said, citing police sources.

Detectives from Portugal’s investigative Policia Judiciaria (PJ) reportedly identified him as a main suspect after phone records showed he had been in the vicinity of the holiday apartment at the time Madeleine went missing on May 3, 2007.

However, he was apparently not on a list of current and former Ocean Club employees handed over to police during the initial investigation and therefore was not questioned at the time.

Officers have questioned his widow about their suspicions and are now said to be conducting searches for Madeleine’s body based on the new evidence, according to the paper.

Portugal police announced last week that they had reopened their investigation into the little girl’s disappearance from the seaside village of Praia da Luz after uncovering potential new lines of inquiry following a cold case review.

"Police suspicions about the former Ocean Club employee arose during the review of the case carried out by a PJ team from Porto,” Correio da Manha said.

"This was the strongest new lead presented to state prosecutors which led to the investigation being reopened.”

The newspaper report continued: "The motives that could have caused the ex-employee to kidnap the youngster are still being investigated. The suspect could have taken the child to commit a sex crime before killing her. But he could also have committed the kidnap as a form of retaliation against the Ocean Club.”

Scotland Yard began its own review of the case in May 2011 and opened a formal investigation in July this year. A new Crimewatch appeal, including the issue of e-fits of two possible suspects, was broadcast earlier this month.

The Metropolitan Police team has singled out 41 “persons of interest” and asked officials in 31 different countries to help them identify the owners of every mobile phone logged in Praia da Luz at the time the child disappeared.

The British detectives have focused part of their efforts on carrying out the first detailed analysis of the mountain of phone data collected by Portuguese officers during the original inquiry.

Madeleine was nearly four when she vanished from her family’s holiday apartment in the Ocean Club complex while her parents, Kate and Gerry, dined with a group of friends in a tapas restaurant nearby.

Clarence Mitchell, the spokesman for the McCann family, said: "We are aware of reports in the Portuguese press. They are pure speculation and the McCanns are not going to give a running commentary on every new report."